Arboretum Sumber Brantas and Cabbage Agricultural Field are conservation areas of Brantas river channel that has set of problem s in the decrease of water quantity and quality and the land degradation. Earthworms has significant role in keeping the soil fertility and it is able to repair the soil’s characteristics. Therefore, the existence of earthworm in the territory need to be known until it can be used as the basis healthier land processing. The soil change of physic-chemistry structures are influential through the earthworm diversity and density in a ecosystem. The ecosystem of Arboretum Sumber Brantas is proceed naturally, while in Cabbage Agricultural Field is proceed by using chemical manure. The purpose of this research in to find out the diversity, density and the relation factors of physic-chemistry with the density of the earthworm those are exist in the Arboretum Sumber Brantas and Cabbage Agricultural Field.

This research was done in April to June 2016. The data collection was taken in Arboretum Sumber Brantas and Cabbage Agriculture Field District Bumiaji Batu City. The identification and the measure of the water soil degree was done in the Optic Laboratory and Ecology Laboratory Department of Biology, Faculty of Science and Technology UIN Malang, while the soil chemistry analysis done in the Chemistry Soil Laboratory of Brawijaya University, Malang. This research is using transect method. The amount of the plot in each research station consist of 30 plots with the distance 5 meter for every plot. The sample was taken by using hand sortir method. The data analysis was using index program of Shannon-Weaner varieties, sort of density (individual/m3), relative density (%) and experiment correlation.

The result of the research shows that the diversity index (H') of earthworms in Arboretum Sumber Brantas is higher, it is 1,08 (medium diversity) while in the Cabbage Agriculture Field is 0,144 (low diversity). The highest worm population density is Pontocolex genus which is exist in Arboretum Sumber Brantas with density values 6.186,7 (individu/m3) and the value of relative density 40,704%. The Correlation between physic-chemistry factors with the density of the worm that shows the positive correlation which is consist of water degree, organic substance, nitrogen, ratio C/N, carbon and potassium, while negative correlation consist of temperature, humidity, pH and phosphor.